Many people who exercise strive to improve their performance. A bicyclist or a sailor, for example, may desire to improve performance by increasing speed over a defined known distance and/or route.
One well-known method exercisers may use to improve performance is to set and strive to reach performance goals. This requires that the exerciser measure performance during the training session and compare the measured performance to the pre-defined goals. For example, if an exerciser desires to increase his or her average running speed, he or she would set an average speed goal, measure an actual average speed during a training session, and then compare the average speed goal with the actual average speed. In this manner, the exerciser is provided with performance feedback that can be used as a guide for future training sessions. To measure actual average speed, an exerciser typically measures an elapsed time of the training session using a stopwatch, measures the distance traveled during the session using a map or landmarks, and divides the distance traveled by the elapsed time. Unfortunately, this requires that the exerciser carry the stopwatch and remember to start and stop the stopwatch at appropriate points during the training session. It also requires that the exerciser determine the distance traveled.
If the exerciser uses a non-standard or arbitrarily-defined course, the distance can sometimes be roughly determined from a vehicle's odometer, though the result may be significantly inaccurate. Where the course cannot be driven with a vehicle, such as, for example, where the course is over open country or over water, some other means of determining distance must be devised. Pedometers, for example, are known in the prior art for measuring distance traveled. Unfortunately, pedometers suffer from a number of disadvantages, including, for example, that they must be properly calibrated; are inaccurate for most forms of movement other than running; and the runner must maintain consistent strides regardless of such factors as changing terrain. Following an arbitrary course can also make repeating the course extremely difficult because the exerciser may not recall the course's exact route. Furthermore, this method makes it very difficult for the user to be aware of performance and progress toward reaching the pre-defined goals during the training session.
Further problems arise, when the exerciser trains in an environment that is affected by environmental parameters such as wind or topography. Topography may comprise for example inclination of a ground surface or flute height. A solution is needed for providing training feedback for the exerciser in such environment.